AMMAN (AFP) - The Jordanian military vowed to avenge the death of one of its pilots, purportedly shown being burned alive in a video released Tuesday by the Islamic State in Iraq and Syria (ISIS) group.

"The blood of the martyr will not have been shed in vain and... vengeance will be proportional to this catastrophe that has struck all Jordanians," said army spokesman General Mamduh al-Amiri.

He was referring to Lieutenant Maaz al-Kassasbeh, a fighter pilot who was captured by ISIS after his jet went down over Syria in December.

State media said he was killed on Jan 3.